Avaliação físico-química das águas do processo de dessalinização de poços salobros e salinos em comunidades rurais do oeste potiguar

Abstract

Resumo: O fornecimento de água potável é o maior desafio das comunidades rurais da região semiárida do Brasil, que são caracterizadas pela escassez de recursos hídricos apropriados para consumo humano. Em uma tendência observada há alguns anos, os Governos Federal e Estadual têm buscado instalar equipamentos de dessalinização das águas salobras subterrâneas para a geração de água doce para o abastecimento de comunidades distantes dos centros urbanos. Desta forma, o objetivo deste trabalho foi avaliar a qualidade das águas oriundas do processo de dessalinização de poços em comunidades rurais do oeste potiguar e seus riscos quanto ao uso na irrigação. A pesquisa foi realizada no período de 2013 e 2014 e, inicialmente, foram identificadas as comunidades abastecidas com as unidades de captação e tratamento de água por dessalinização, através de um levantamento cadastral. Para isto, foram realizadas quatro campanhas de coletas em diferentes períodos do ano para avaliação da qualidade das águas potável do tratamento por osmose reversa, poço e rejeito salino, dentro de cada período. Foram analisados parâmetros físico-químicos das águas para fins de irrigação. As águas foram classificadas quanto ao uso na irrigação; aos riscos de problemas de infiltração no solo causados pela sodicidade da água e toxicidade em plantas. As estações de tratamento de água por osmose reversa nas comunidades rurais monitoradas produziram uma água dessalinizada com concentrações baixas de sais, com 68% do total das amostras na classe de classificação C1S1; 25% na classe C2S1 e; apenas 7% na classe C3S1. Com relação ao rejeito gerado, 93% das amostras de água de rejeito se classificaram como C3 ou C4 nos quatro períodos de coleta, ou seja, águas de alto ou extremamente alto risco de salinização.. Palavras-chave: Salinidade. Osmose reversa. Água residuária. Abstract:The supply of drinking water is the biggest challenge of rural communities in semiarid region of Brazil, which are characterized by the scarcity of water resources suitable for human consumption. A trend a few years ago, the federal and state governments have sought to install desalination equipment of underground brackish water to generate fresh water to supply more distant communities from urban centers. Thus, the objective of this study was to evaluate the quality of water wells desalination process in rural communities from Potiguar West. This research was conducted between 2013 and 2014. At first, the communities which were supplied by catchment and treatment of desalinated water centers were registered through a cadastral survey. In order to do so, four data collection expeditions took place in different periods as well as the evaluation of a) the reverse osmosis treated water quality, b) the well, c) the reject brine Physicochemical attributes of water for irrigation was also analyzed. The waters were classified according to its use for irrigation; leakage risks and toxicity in plants In the monitored rural communities, the reversed osmosis water treatment stations produce de...

Hydrochemical Characterization of Water Resources From Reverse Osmosis Desalination Plants

“…The waters of this group present severe restriction regarding salinization due to their high EC w , whose values make practically impracticable the use of these water for irrigation. In similar works, Oliveira et al (2017) and Anders et al (2017) found that between the wells analyzed, respectively 93.60 and 90% of the wastewater samples from desalinators presented increasing or severe risk of soil salinization. The authors state that these waters are not suitable for irrigation under normal conditions and may be used on soils with good drainage, provided that adequate leaching depth is applied and salt tolerant crops are used.…”

“…Group 2 was formed by the smallest sum of squares of LSI and was composed of samples collected in the community of Boa Fé (BF1, BF2, BF3, and BF4). In this group all the samples presented a high risk of salinization, since their EC w values (6.20, 6.40, 6.20 and 5.72 dS m -1 ) (Table 4) restrict their use in irrigation, except in specific conditions of management (Terceiro Neto et al, 2013) like the mixture of water of different salinities, cultivation of salinity-tolerant plants (Dias, Ferreira, Liu, & Suarez, 2016), or the use in hydroponic farming systems (Oliveira et al, 2017).…”

“…Although groundwater can be used for consumption and also for agricultural production, guaranteeing the food and nutritional security of rural families, these water sources present in most cases restrictions of use for human consumption due to high-salinity problems (Oliveira et al, 2017).…”

A proposed index to assess quality of waters from desalination plants

“…This community and period also had the lowest value of IRQI among the samples of brackish well water (0.29). Oliveira et al (2017) classified the water of this well as with no risk of salinity and toxicity by sodium and chlorides, but with accentuated risk of infiltration problems due to its EC, compared with the SAR.…”

Management of water resources in semi-arid: assessment of the drinking water supply in rural communities of Chapada do Apodi-RN

“…The Conama Resolution 357/2005 and the Ordinance No. 2,914 / 2011 do not assign reference values for salinity in relation to potability, but according to this Resolution, the values presented in the analysis according to the average obtained are classified as freshwater, which are classified byOliveira et al (2017) as good for irrigation practices, once they present few restrictions of use, and low risk of developing salinity problems(OLIVEIRA et al, 2017). Thus, regarding salinity, the investigated water samples are related as compatible with the most demanding uses(PESSÔA, 2013).The values obtained for total coliforms -C. Totals averaged 149.266 CFU/100mL(Table 3), with values of at least 100.0 CFU/100mL, as the rural communities of Soledade, analysis 01 (Row 63 and Column 11,Table 3); Soledade, analysis 02 (Row 64 and Column 11, fromTable 3); Soledade, analysis 04 (Row 66 and Column 11, fromTable 3); and Soledade, analysis 08 (Row 70 and Column 11, ofTable 3).…”